Method for making embedded hydrogel contact lenses

A method for producing embedded hydrogel contact lenses, comprising the steps of:

• (1) obtaining a first lens-forming composition and a second lens-forming composition, wherein the first and second lens-forming compositions comprise identical polymerizable components (materials) but different non-reactive diluents, wherein the first lens-forming composition comprises a first non-reactive diluent and the second lens-forming composition comprises a second non-reactive diluent, wherein difference (ΔCi) in the concentration of each polymerizable components (materials) between in the first lens-forming composition and in the second lens-forming composition is less than 10.0%, wherein
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• in which C1i and C2i are the concentrations of polymerizable component i in the first and second lens-forming compositions respectively, wherein ratio of the viscosity of the first lens-forming composition over the viscosity of the second lens-forming composition is at least 1.5;
• (2) obtaining a lens mold, wherein the lens mold comprises a female lens mold half and a male lens mold half, wherein the female lens mold half has a first molding surface and a first central axis, wherein the male lens mold half has a second molding surface and a second central axis, wherein the first molding surface defines the anterior surface of an embedded hydrogel contact lens, wherein the second molding surface defines the posterior surface of the embedded hydrogel contact lens, wherein the female and male lens mold halves are configured to receive each other such that a mold cavity is formed between the first and second molding surfaces when the mold is closed;
• (3) obtaining an insert which is made of a polymeric material and comprises a front surface, an opposite back surface, a third central axis, and a diameter up to about 13.0 mm;
• (4) dosing from about 1 to about 20 μL of the first lens-forming composition in the center of the first molding surface of the female lens mold half;
• (5) placing the insert on top of the first lens-forming composition on the first molding surface of the female lens mold half in a way to ensure that the third central axis coincides with the first central axis and the insert is held at a position above the first molding surface of the female lens mold half;
• (6) placing the male lens mold half on top of the female lens mold half and closing the male and female lens mold halves to form a molding assembly comprising the first and second lens-forming compositions and the insert immersed therein in the molding assembly;
• (7) curing the first and second lens-forming compositions in the molding assembly to form an embedded hydrogel lens precursor that comprise a bulk hydrogel material formed from the first and second lens-forming compositions and the insert embedded in the bulk hydrogel material and centered in the embedded hydrogel lens precursor;
• (9) separating the lens mold obtained in step (8) into the male and female lens mold halves, with the embedded hydrogel lens precursor adhered on a lens-adhered lens mold half which is one of the male and female lens mold halves;
• (10) removing the embedded hydrogel lens precursor from the lens-adhered lens mold half (preferably before the embedded hydrogel lens precursor is contact with water or any liquid);
• and (11) subjecting the embedded hydrogel lens precursor to post-molding processes including a hydration process and one or more other processes selected from the group consisting of extraction, surface treatment, packaging, sterilization, and combinations thereof to form the embedded hydrogel contact lens.